from reportlab.pdfgen.canvas import Canvas
from reportlab.pdfbase import pdfmetrics
from reportlab.pdfbase.cidfonts import UnicodeCIDFont
pdfmetrics.registerFont(UnicodeCIDFont('STSong-Light'))
canvas = Canvas('watermark.pdf')
canvas.setFont('STSong-Light', 16)
canvas.drawString(20, 20, "麦叔出品")
canvas.save()
